Technical Science - Term 4 - Week 8

An electrical circuit consists of several key components: a power source (like a battery), conductors (wires), and loads (devices that use electricity, such as bulbs or motors). The power source provides the energy needed for the circuit to function, while conductors allow the flow of electric current. Loads convert electrical energy into other forms of energy, such as light or motion.

There are two primary types of circuits: series and parallel. In a series circuit, components are connected end-to-end, meaning the same current flows through each component. If one component fails, the entire circuit is interrupted. In contrast, a parallel circuit has multiple paths for current to flow. If one path is interrupted, current can still flow through other paths, allowing the circuit to continue functioning.

Ohm's Law is a fundamental principle in electronics that relates voltage (V), current (I), and resistance (R) in a circuit. It states that V = I × R. This means that the voltage across a conductor is directly proportional to the current flowing through it, provided the temperature remains constant. Understanding this law is crucial for analyzing and designing electrical circuits.

Consider a simple series circuit with a 9V battery and two resistors of 3Ω and 6Ω. The total resistance (R_total) is the sum of the individual resistances: R_total = 3Ω + 6Ω = 9Ω. Using Ohm's Law, we can find the current (I) flowing through the circuit: I = V / R_total = 9V / 9Ω = 1A. Therefore, the current flowing through the circuit is 1 ampere.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 12Ω, the total resistance can be calculated using the formula: 1/R_total = 1/R1 + 1/R2. This gives us 1/R_total = 1/4 + 1/12, which simplifies to 1/R_total = 3/12 + 1/12 = 4/12. Thus, R_total = 12/4 = 3Ω. The current through each resistor can then be calculated using Ohm's Law.

Let's work together on a problem. We have a series circuit with a 12V battery and two resistors of 2Ω and 4Ω. First, calculate the total resistance: R_total = 2Ω + 4Ω = 6Ω. Now, apply Ohm's Law to find the current: I = V / R_total = 12V / 6Ω. What is the current flowing through the circuit?

Now it's your turn! Solve the following problems independently: 1) A circuit has a 24V battery and two resistors in series, 5Ω and 10Ω. Calculate the total resistance and the current. 2) In a parallel circuit with a 9V battery and two resistors of 3Ω and 6Ω, find the total current flowing from the battery.

• To store electrical energy
• To limit current flow
• To increase voltage
• To convert energy to heat

Answer: To limit current flow

Resistors are used to control the amount of current flowing through a circuit.

• Only that component stops working
• The entire circuit is interrupted
• The current increases
• The voltage drops

Answer: The entire circuit is interrupted

In a series circuit, all components are connected in a single path, so a failure in one component stops the flow of current.

Answer: V = I × R

Ohm's Law states that the voltage across a conductor is equal to the product of the current flowing through it and the resistance.

• 3Ω
• 4Ω
• 12Ω
• 16Ω

Answer: 3Ω

The total resistance in a parallel circuit is calculated using the formula 1/R_total = 1/R1 + 1/R2.

Answer: The total current increases.

Adding more branches in a parallel circuit provides additional paths for current to flow, increasing the total current.

• It doubles
• It halves
• It stays the same
• It quadruples

Answer: It doubles

According to Ohm's Law, if voltage increases and resistance remains constant, current will also increase proportionally.

• Resistor
• Capacitor